Background
The ideal outcome of nerve coaptation in vascularized composite allotransplantation (VCA) is complete and immediate recovery, but surgeons are largely resigned to the expectation that motor and sensory functional recovery will be incomplete and protracted This project aimed to synthesize a current paradigm for nerve coaptation, and to determine whether the latest technology and basic science research warrant a new, future paradigm that can finally realistically aim for nerve recovery that is complete and immediate.
Methods
For this study, “regeneration” is the process of axonal sprouts advancing toward the target organ (necessary because Wallerian degeneration rapidly destroys the nerve distal to the injury), while “repair” is the re-establishment of axonal membranous continuity (prior to the onset of Wallerian degeneration) The current paradigm and the proposed future paradigm were synthesized from primary resources from multiple databases (Pubmed, Google Scholar, SEC filings, and the US Patent and Trademark Office), as well as from personal communication with key thought-leaders.
Results
The current paradigm for nerve coaptation focuses on optimizing the innate regenerative process In the research setting, this is done by manipulation of the local microenvironment In clinical practice, this is done by placement of epineurial sutures This regenerative approach, however, fails to address axonal discontinuity, and therefore has a low likelihood of effective recovery The future paradigm, in contrast, could instead focus on actual axonal membranous repair Early pre-clinical research has been identified that has achieved axonal membranous fusion, and in doing so has immediately reestablished electrical conduction and prevented Wallerian degeneration.
Conclusions
This study has found that recent advancements are making it possible to finally address axonal discontinuity, and therefore a new, future paradigm for nerve coaptation that focuses on “repair” as opposed to only “regeneration” is in fact warranted By restating and clarifying the ultimate goal of nerve coaptation, this new paradigm will hopefully serve as a framework for clinical and research efforts in VCA in the 21st century.